Seal systems using gasket devices are well known and have been used in a variety of applications to prevent fluid from leaking between joined pieces. For example, a seal device is interposed and compressed between flanged end connections of a flow line. In some cases, in-line process control equipment is to be installed at various points in a flow line, and may be associated with flanged end connections of a flow line. Inline process control equipment may include such things as valves, pumps, flow meters, temperature controllers, pressure controllers and the like. In addition, ends of pipe sections are provided with flanges so that the sections may be connected, end-to-end, to form the flow line. It is known to provide gasket devices at the interfaces of the joined sections to prevent leakage of the fluid at the joint.
Regardless of the nature of the joint, that is, whether it is between the joined sections of pipe or whether the joint is used to connect in-line process control equipment, it is desirable for a gasket device and seal system to be selected based on various factors that are associated with a particular joint and the particular media that is conveyed through the joint. These factors include the corrosive nature of the media flowing through the pipe line as well as the physical characteristics of that flowing media. Such physical characteristics include the pressure, temperature and velocity of the media. Additionally, in many cases it is also necessary not only to provide a reliable seal for the joint but also electrically isolate one side of the joint from the other. For example, a well known method of corrosion resistance for pipelines is cathodic protection. This method of corrosion protection requires sealing joints that provide electrical isolation. Another example is when two sides of the joint are of dissimilar metals. In this case the electrical potential difference between the two metals can create a galvanic corrosion cell if the two sides are not electrically isolated. Finally, it is also desirable for a sealing joint to provide an effective seal during the event of a fire. Fires pose a very serious threat to the safety of the pipeline workers and become even more dangerous if the sealing elements between joints are not capable of containing the media during a fire.
Therefore, flow line sealing systems face numerous challenges. For example, many materials which resist corrosive gases are not suitable for high pressure applications since the materials deform. Materials which are less prone to deformation, such as a graphite filled spiral wound metal seal, conduct electricity. Many materials that are used to create seal systems may melt at high temperatures, such as those that would result in a fire, so that the seal between flanges is compromised. This is an extremely dangerous situation since compromise of the seal system allows the media, such as a petroleum or gas product, to rapidly leak from the flow line which can increase the available combustion products for such a fire. Therefore, a sealing system that can contain high pressures, electrically isolate and provide safety during a fire would be a significant improvement in the field of effective flow line sealing.